Text threading is already indicated in the layout view with little symbols in the in and out ports of the frames, and you can show the connecting lines if you like. The end of a story is indicated by the non-printing # character that is visible when you show non-printing characters. There is no marker for threading inside the text, but the various breaks also have non-printing characters that can be revealed.

That's great thanks, but I'm after characters that are visible when printed, I've seen it throughout several magazines, where an article spans 2 or more pages and the text continuation is indicated by an arrow or forward symbol at the end of the last column, and also symbols to indicate when the article has ended. I'm sure there's a term for this in publishing, and wondered if it was something that could be achieved in InDesign, saves doing it manually.

Dingbat is a general term for a pictorial glyph, and is not reserved for the end of a story. I'm not sure there is any consensus on a term for one in that position, but as I said, "bug" is commonly used among printers I know.

You could consider putting the glyph on your master page. if it's on the same layer as the text, it would behind it rather than in front but text wrap would still work, though overriding it would be a bit of a hassle for changing or deleting it. Adding another layer above the regualr text, as you might need to do with a page number marker that needs to appear in front of a background image, is another possibility and would keep it accessible.